Implement lift hitch

ABSTRACT

An implement is hitched to the lift assembly of a vehicle such as a tractor by cooperating lift hitches which establish a pivotal connection between the implement and the lift assembly. Each lift hitch includes rigid links pivotally fastened to the implement and provided with slots that operably engage a lift pin of the lift assembly to suspend the links from the lift pin. A tension spring interconnects the links to maintain the links in inverted V-shaped configuration when coupled to the lift pin and to prevent accidental dislodgement of the lift pin from the slots in the links. The slots each include a circular segment and an entrance opening narrower than the diameter of said segment for receiving a large diameter resilient sleeve which is loosely journaled on the lift pin and is deformed as it is moved through the narrow entrance opening but returns to its normal circular shape when rotatably received in the circular segments of the cooperating links.

United States Patent [191 Feders piel IMPLEMENT LIFT HITCH Joseph A. Federspiel, Port Washington, Wis.

[75] Inventor:

[52] US. Cl 56/15.2, 56/DIG. 9, 56/DIG. 22, 172/273 [51] int. Cl A01d 55/28 [58] Field of Search 56/l6.3, 14.9, 15.2, 15.7, 56/DIG. 9, DIG. 22; 172/272, 273

[56] References Cited UNITED STATES PATENTS 2,376,541 5/1945 Johnson et al 56/DIG. 9

2,743,654 5/1956 Mason 172/273 3,283,486 ll/l966 Marek et al. 56/l6.3

3,522,694 8/1970 Horn i 56/DIG. 22 3,61 L682 lO/l97l lsaacson et al. 56/14.9 3,654,749 4/1972 Ostergren et al. 56/DlG. 22

[451 Mar. 12, 1974 Primary Examiner-Antonio F. Guida Attorney, Agent, or Firm-C. E. Tripp 57 ABSTRACT- An implement is hitched to the lift assembly of a vehicle such as a tractor by cooperating lift hitches which establish a pivotal connection between'the implement and the lift assembly. Each lifthitch includes rigid links pivotally fastened to the implement and provided with slots that operably engage a lift pin of the lift assembly to suspend the links from the lift pin. A tension spring interconnects the links to maintain the links in inverted V-shaped configuration when coupled to the lift pin and to prevent accidental dislodgement of the lift pin from the slots in the links. The slots each include a circular segment and an entrance opening narrower than the diameter of said segment for receiving a large diameter resilient sleeve which is loosely journaled on the lift pin and is deformed as it is moved through the narrow entrance opening but returns to its normal circular shape when rotatably received in the circular segments of the cooperating links.

13 Claims, 5 Drawing Figures PAIENTEDm 12 I974 'sam1nr2 IMPLEMENT LIFT HITCH CROSS REFERENCE TO RELATED APPLICATIONS The subject matter of the present application is partially illustrated in my copending US. Pat. application Ser. No. 304,l73 filed Nov. 6, 1972 and Ser. No.

307,918 filed Nov. 20, 1972; which-applications are assigned to the assignee of the present invention.

BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION The present invention relates to an implement lift hitch particularly suited for hitching an implement to the lift assembly of a vehicle such as a tractor.

2. DESCRIPTION OF THE PRIOR ART Certain vehicles such as tractors have powered lift assemblies that support implements, such as mowers, under their bodies. Existing lift hitches for hitching the implements to the lift assemblies have, in general, used removable pivot pins and retainers to establish the desired hitch connections. These removable parts can be lost, and in many cases it is necessary to use tools which are not always available to connect or disconnect the hitch from the lift assembly. Some existing hitches have been spring loaded pins that occupy a substantial amount of space which is not always readily available in compact tractor models. Many hitches include vertical hitch posts rigidly secured to the implement which can impede the hitching and unhitching procedure. For example, these posts make it difficult to place the implement under the vehicle so that the implement may be hitched to the lift assembly. In many cases the vehicle is driven backwards over the implement until the lift assembly overlies the implement and is then hitched to the lift'assembly. However, in some cases the implement is wider than the tractor and, accordingly, must be slid transversely under the tractor before the implement can be hitched to the lift assembly.

The existing hitches are not altogether satisfactory for the reasons outlined above. It is therefore desirable to provide a hitch that has no removable parts and can be coupled or uncoupled from the lift assembly without the aid of any tools. It is further desirable to provide a hitch that is retractable below the upper surface of the implement so that the implement may be readily moved under the vehicle without danger of the hitch contacting any portion of the vehicle.

SUMMARY OF THE INVENTION The present invention provides an improved lift hitch for connecting an implement to a vehicle mounted lift assembly. The improved hitch utilizes links pivoted to an implement from a retracted position below the upper portions of the implement into an inverted V- shaped position projecting above the implement. Right and left hand hitch assemblies are preferably used in the preferred embodiment and each hitch assembly includes a pair of hitch links that cooperate to establish pivotal connection between the implement and a pivot pin on the lift assembly. Each hitch link includes a slot which receives the aforementioned pivot pin to provide a pivotal connection between the two elements. Provision is made for preventing accidental release of the hitch connections'by shock forces or the like transmitted to the hitch connection during normal use of the vehicle and/or implement.

Accordingly, it is a general object of the present invention to provide an improved implement lift hitch adapted for hitching an implement to the lift assembly of a vehicle such as a tractor when in use and adapted to be folded below the upper limits of the implement when not in use.

Another object of the invention is to provide means for firmly coupling a lift hitch to the lift assembly of a tractor without the aid of any tools and without requiring the removal of any parts.

The above and other objects of the present invention will be made apparent from the following description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE'DRAWINGS FIG. 1 is a side elevation of a tractor having a mower connected to the tractors lift assembly by the lift hitch of the present invention.

FIG. 2 is an enlarged section taken along lines 2-2 of FIG. 3 illustrating one of the lift hitch assemblies connected to a fragment of the lift assembly.

FIG. 3 is a plan of the lift hitch illustrated in FIG. 2, certain parts being cut away.

FIGS. 4 and 5 are enlarged operational views in section illustrating the manner in which one of the hitch arms is connected to the lift sleeve and pin of the associated lift assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates the lift hitch 15 of the present invention associated with a tractor or vehicle 18 provided with a lift assembly 19 that includes a shaft 20 journaled on the chassis 21 of the tractor. The lift assembly 19 is described in detail in my copending US. Pat. application Ser. No. 307,418 filed Nov. 17, I972.

The lift assembly 19 includes a right hand pair of lift arms 22 on the right side of the vehicle, andan identi cal pair of lift arms (not shown) on the left side of the vehicle. These right and left hand lift arms cooperate with identical right and left hand lift hitches or hitch assemblies 15. Since the lift assemblies and hitch assemblies on the right and left sides of the vehicle are identical, only the right hand components will be described in detail. However, it will be understood that both right and left hand components are used to connect the implement to the lift assembly of the tractor.

The right lift arm 22 of the lift assembly 19 include spaced members 22a, 22b as best shown in FIGS. 2 and 3. The members 22a and 22b are mounted on the shaft 20 which is pivoted by a hydraulic power unit 23 (FIG. 1) to pivotally raise and lower the lift arm 22. A powered rotary mower 24, shown resting on the ground under the vehicle 18, is hitched to the lift assembly 19 by the lift hitch 15 of the present invention, and by two drag links 26, only one link being shown. As mentioned above, the implement 24 is hitched to the lift assembly by two identical hitch assemblies 15.

The implement or mower 24 is of standard well known design and includes cutters (not shown) which are driven from the tractors engine through a belt driven power takeoff 28 and a telescoping flexible drive shaft 30.

The upper end of each drag link 26 (only one being shown) is pivoted on a pin 36 secured to supports 38 depending from the vehicles front axle. Each drag link 26 is pivoted on a pin 40 supported by the mower housing 42.

Each pair of lift arms 22 of the lift assembly supports a lift element that includes a lift pin 44 as indicated in FIGS. 2 and 3. The lift pin 44 is mounted within aligned holes in the spacedmembers 22a, 22b of the lift arms 22 and is loosely encircled by a resilient plastic or metal sleeve 48 that is slightly larger in internal diameter than the diameter of the pin 44. The pin 44 is retained on the lift arm 22 by snap rings 50,52 received in grooves on the periphery of the pin.

The right and left hand hitch assemblies each includes two links 56,58 pivotally connected to associated hangers 59 of the mower housing for pivotal movement about the axes of cap screws 60 and 64, re-

spectively. Each screw 60,64 is encircled by a sleeve (not shown) fitted in the associated hanger and link holes to provide a bearing for links 56,58. A washer 66 encircles the screw 60 and serves as a spacer for laterally separating the lower end of the link 56 from the hanger 59.

As indicated in FIGS. 2 and 3, the upper ends of each pair of hitch links 56,58 are provided with slots 68,70 leading from the inner edges 56a,58a of the links. Each slot 68,70 has a segmental circular portion 71 of a diameter slightly larger than a contiguous entry slot portion 71a leading from the edge of the link to the circular portion 71. The diameter of the segmented circular portion 71 of the links 56,58 is substantially the same as the diameter of the sleeve 48 which fits within the slots 68,70 as indicated in FIG. 5. The upper ends of hitch links 56,58 are suspended from the lift pin 44 with the segmented circular portion of the slot in each link 56,58 embracing the lift pin 44 and sleeve 48 to thereby cause the associated lift pin 44 to support the hitch links 56,58. A tension spring 72 is interconnected between links 56,58 with the ends 72a, 72b of the spring anchoredin retaining holes in links 56,58. The spring 72 urges link 56 clockwise and link 58 counterclockwise as viewed in FIG. 2 to act as retaining means which prevent accidental dislodgement of the lift pin 44 and sleeve 48 from the embracing slots of links 56,58 due to shock forces acting on the implement 24.

Each spring 72 is strong enough to hold the associated links 56,58 into firm engagement with the associated pin and sleeve so that they will not jar loose during routine use of the tractor and implement. However, the spring 72 will allow the link 56 to be pivoted counterclockwise away from the lift pin 48 and will allow the link 58 to be pivoted clockwise away from the pin 44 when it is desired to separate the links 56,58 from the lift pin 44 in order to unhitch the implement 24 from the tractor 18.

It has been determined that the spring 72 interconnects the links 56,58 with sufficient force to maintain the links in reliable hitching engagement with the pin 44. even though the resilient locking sleeve 48 is omitted from the assembly. However, the resilient sleeve 48 provides greater assurance that the pin 44 will not be dislodged from the slots when excessive forces are ap-. plied to either the implement or the vehicle.

The manner in which each pair of hitch links 56,58 is engaged with the lift pins 44 to suspend the mower 24 is best explained by reference to FIGS. 4 and 5 which illustrate the progressive steps of connecting link 56 to the pin 44 of lift arm 22. Basically, the link 56 is pivoted downward about screw 60 (FIG. 2) to move the slot 68 of link 56 into embracing relation with the lift pin 44 as indicated in FIG. 4 thereby causing the pin 44 and sleeve 48 to enter link slot 68. As the sleeve 48 moves into the entry portion 7 la of slot 68 the sleeve is resiliently deformed by the narrow slot edges and assumes an elliptical configuration as shown in. FIG. 4. When the pin and sleeve move out of the narrow entry slot and enter the circular segmental portion of the slot, as indicated in FIG. 5, the sleeve 48 snaps back into its original circular shape making it difficult to unintentionally dislodge the pin 44 from the link slot 68. Thus the sleeve 48 serves as a retaining means for minimizing accidental separation of the lift element from the slot 68. The slot 70 of the other link 58 is moved into embracing relation with associated lift pin 44 in a manner similar to that which has just been described.

The implement lift hitch facilitates rapid hitching of a mower or other implement 24 (FIG. 1) to the vehicles lift assembly 19. In order to connect the mower 24 to the vehicle 18, which mower is wider than the vehicle, the mower is first slid transversely under the vehicle between the front and rear wheels into position to be alignedwith the vehicle s lift assembly 19. The drive shaft 30 is then connected between the cutters and the output shaft of the power take-off 28, and the two drag links 26 are pivotally interconnected to the respective drag link pins 36,40. The links 56,58 of the right and left pairs of hitchassemblies 15 are then manuallygripped and pivoted to stretch the tension spring 72 until the links 56 and 58 are disposed on opposite sides of the associated lift pin 44 and sleeve 48. The upper ends of each link 56,58 are then pivoted in opposite directions and downwardly a slight amount until the resilient sleeve 48 and lift pin 44 of the lift element are fully seated within link slots 68,70 in the manner indicated in FIG.'2. Thus, each pair of links 56,58 is hitched to a respective lift pin 44 and each pair of links 56,58 provides a pivotal connection between the associated pin 44 and the implement 24. v

The procedure for unhitching the links 56,58 from the pins 44 involves lowering the implement 24 onto the ground, gripping the links 56,58 and pivoting them in reverse to uncouple the hitch slots 68,70 from the lift pins 44 and their sleeves 48. The spring 72 then pivots the links 56 and 58 downwardly below the upper surface of the mower 24.

Although the best mode contemplated for carrying out the present invention has been herein shown and described, it will be apparent that modification and variation may be made without departing from what is regarded to be the subjectmatter of the invention.

I claim l. A lift hitch for connecting an implement to the lift assembly of a vehicle comprising: a lift element carried by said lift assembly, a pair of links, means pivotally connecting one end of each link to the implement at spaced points along said implement, means defining a slot in the other end of each of said links for receiving said lift element upon pivotal movement of said links into a hitching position, and retaining means for releasably retaining said slots in engagement with said lift element for precluding accidental dislodgement of said lift element from said slots.

2. A lift hitch according to claim 1 wherein said retaining means is deformable and serves to oppose dislodgement of the lift element from the slots.

3. A lift hitch according to claim 1 wherein said retaining means is a spring connected between said links for urging the slots of said links into firm engagement with said lift element.

4. A lift hitch according to claim 1 wherein each slot includes a relatively narrow entrance portion which leads into a circular segmented portionhaving a larger diameter than the width of said entrance portion; wherein said lift element is a lift pin; and wherein said retaining means is a deformable member on said lift pin having an outer cylindrical surface which is larger in diameter than the width of said entrance portion, said deformable member being deformed when it is moved through said entrance portions of each slot.

5. A lift hitch according to claim 4 wherein said deformable member is a resilient sleeve loosely fitted around said lift pin.

6. A lift hitch according to claim 4 wherein said retaining means additionally includes a spring connected between said links for urging the slots of said links into firm engagement with said lift element.

7. A lift hitch according to claim 5 wherein said retaining means additionally includes a spring connected between said links for urging the slots of said links into firm engagement with said lift element.

8. A lift hitch according to claim 1 wherein said slots may be disengaged from said lift element by lowering the lift element and pivoting the links in opposite directions away from said lift element.

9. A lift hitch according to claim 7 wherein said slots may be disengaged from said lift element by lowering the implement to the ground and by thereafter manually overcoming the retaining force-and pivoting the links in opposite directions away from said lift element.

10. A lift hitch according to claim 3 wherein said spring pivots said links to a folded position below the level of the upper surface of said implement when the links are spaced from said lift element and are released from external forces.

1 1. A lift hitch according to claim 3 wherein the links slant downwardly in opposite directions from said lift element, and said spring is a tension spring.

12. A lift hitch for hitching an implement to a vehicle mounted lift assembly comprising: a lift element car- .ried by said lift assembly, two links each having a slotbeing pivotable about its pivoted end to a coupling position wherein its slotted end engages the above mentioned lift element, each link being pivotable from said coupling position to a disengaged position wherein its slotted end is spaced from the aforementioned lift element and thereby disconnect such link from the aforementioned lift element, and resilient means for urging said slotted ends into said coupling position.

13. A lift hitch for establishing a hitch connection between an implement and a vehicle mounted lift assembly, said lift hitch comprising: a first hitch link having a first end pivotally secured to the implement and having a second end adapted to establish a hitch connection with said lift assembly, a second hitch link having a first end pivotally secured to the implement and having a second end adapted to establish a hitch connection with the aforesaid lift assembly, said links being adapted to cooperate to establish a single hitch connection with the said lift assembly in such manner that the links connect said implement to said lift assembly, said links being'adapted to be pivoted into hitching positions wherein they each form a hitch connection to the aforesaid lift assembly and are precluded from pivotal movement relative to each other until manually pivoted out of said hitching positions. 

1. A lift hitch for connecting an implement to the lift assembly of a vehicle comprising: a lift element carried by said lift assembly, a pair of links, means pivotally connecting one end of each link to the implement at spaced points along said implement, means defining a slot in the other end of each of said links for receiving said lift element upon pivotal movement of said links into a hitching position, and retaining means for releasably retaining said slots in engagement with said lift element for precluding accidental dislodgement of said lift element from said slots.
 2. A lift hitch according to claim 1 wherein said retaining means is deformable and serves to oppose dislodgement of the lift element from the slots.
 3. A lift hitch according to claim 1 wherein said retaining means is a spring connected between said links for urging the slots of said links into firm engagement with said lift element.
 4. A lift hitch according to claim 1 wherein each slot includes a relatively narrow entrance portion which leads into a circular segmented portion having a larger diameter than the width of said entrance portion; wherein said lift element is a lift pin; and wherein said retaining means is a deformable member on said lift pin having an outer cylindrical surface which is larger in diameter than the width of said entrance portion, said deformable member being deformed when it is moved through said entrance portions of each slot.
 5. A lift hitch according to claim 4 wherein said deformable member is a resilient sleeve loosely fitted around said lift pin.
 6. A lift hitch according to claim 4 wherein said retaining means additionally includes a spring connected between said links for urging the slots of said links into firm engagement with said lift element.
 7. A lift hitch according to claim 5 wherein said retaining means additionally includes a spring connected between said links for urging the slots of said links into firm engagement with said lift element.
 8. A lift hitch according to claim 1 wherein said slots may be disengaged from said lift element by lowering the lift element and pivoting the links in opposite directions away from said lift element.
 9. A lift hitch according to claim 7 wherein said slots may be disengaged from said lift element by lowering the implement to the ground and by thereafter manually overcoming the retaining force and pivoting the links in opposite directions away from said lift element.
 10. A lift hitch according to claim 3 wherein said spring pivots said links to a folded position below the level of the upper surface of said implement when the links are spaced from said lift element and are released from external forces.
 11. A lift hitch according to claim 3 wherein the links slant downwardly in opposite directions from said lift element, and said spring is a tension spring.
 12. A lift hitch for hitching an implement to a vehicle mounted lift assembly comprising: a lift element carried by said lift assembly, two links each having a slotted end and a pivoted end, means pivotally connecting the pivoted ends of said links to said implement at spaced points along said implement, said slotted end of each link being adapted to engage said lift element of the vehicle mounted lift assembly whereby both links may be suspended from said lift element, each link being pivotable about its pivoted end to a coupling position wherein its slotted end engages the above mentioned lift element, each link being pivotable from said coupling position to a disengaged position wherein its slotted end is spaced from the aforementioned lift element and thereby disconnect such link from the aforementioned lift element, and resilient means for urging said slotted ends into said coupling position.
 13. A lift hitch for establishing a hitch connection between an implement and a vehicle mounted lift assembly, said lift hitch comprising: a first hitch link having a first end pivotally secured to the implement and having a second end adapted to establish a hitch connection with said lift assembly, a second hitch link having a first end pivotally secured to the implement and having a second end adapted to establish a hitch connection with the aforesaid lift assembly, said links being adapted to cooperate to establish a single hitch connection with the said lift assembly in such manner that the links connect said implement to said lift assembly, said links being adapted to be pivoted into hitching positions wherein they each form a hitch connection to the aforesaid lift assembly and are precluded from pivotal movement relative to each other until manually pivoted out of said hitching positions. 